The present invention relates to a device for delivering ink, more particularly on a print head for an ink jet printer, provided with a series of ink delivery nozzles which can be actuated selectively in the printing of a sheet of paper or the like.
The present invention also relates to an ink jet printer provided with such a print head device.
The present invention also relates to a method of making such a print head device.
A device of this kind is known inter alia from U.S. Pat. No. 4,364,067. In one embodiment, the print head comprises a base member or plate, which is substantially triangular in cross-section, and which is disposed with the apex towards the paper for printing. The device has two ink inlets situated at the top ends of the oblique sides and connected to an ink reservoir, with each leading into an ink distribution chamber, to which are connected a number of ducts formed in the associated oblique side. In the plane of the associated oblique side these ducts converge in an arc towards a number of obliquely extending ink delivery nozzles. Thus the head surface of the base plate is provided with two rows of obliquely directed ink delivery nozzles which are offset from each other.
The ducts are each provided with a constriction and a pressure chamber situated directly downstream thereof. The ducts are covered by a vibrating plate on which an electrode is disposed. At the pressure chambers, piezo-electric elements provided with an electrode are mounted on the first-mentioned electrode. By selective actuation of the piezo-electric elements the vibrating plate is pressed in locally and the volume of the pressure chamber in the required duct is reduced so that a specific quantity of ink is propelled through said duct to the associated ink delivery nozzle.
The mutually offset arrangement of the two rows of ink delivery nozzles requires a high accuracy of adjustment and operation of the known print head, particularly the height with respect to the paper. Moreover, the designing and making of the ducts in the two sides is complicated, particularly if the print head is to be very wide, for example to be able to cover a page width.